LYGIA Shader Library

Dependencies:

• lygia/math/absi.glsl
• lygia/sampler.glsl

Use:

<vec4> pyramidDownscale(<SAMPLER_TYPE> tex, <vec2> st, <vec2> pixel)

Check it on Github

#ifndef PYRAMID_H1
#define PYRAMID_H1 1.0334, 0.6836, 0.1507
#endif

#ifndef PYRAMID_SAMPLE_FNC
#define PYRAMID_SAMPLE_FNC(TEX, UV) SAMPLER_FNC(TEX, UV)
#endif

#ifndef PYRAMID_DOWNSCALE_SAMPLE_FNC
#define PYRAMID_DOWNSCALE_SAMPLE_FNC(TEX, UV) PYRAMID_SAMPLE_FNC(TEX, UV)
#endif

#ifndef FNC_PYRAMID_DOWNSCALE
#define FNC_PYRAMID_DOWNSCALE
vec4 pyramidDownscale(SAMPLER_TYPE tex, vec2 st, vec2 pixel) {
    const vec3 h1 = vec3(PYRAMID_H1);

    vec4 color = vec4(0.0);
    for (int dy = -2; dy <= 2; dy++) {
        for (int dx = -2; dx <= 2; dx++) {
            vec2 uv = st + vec2(float(dx), float(dy)) * pixel * 0.5;
            if (uv.x <= 0.0 || uv.x >= 1.0 || uv.y <= 0.0 || uv.y >= 1.0)
                continue;
            color += PYRAMID_DOWNSCALE_SAMPLE_FNC(tex, uv) * h1[ absi(dx) ] * h1[ absi(dy) ];
        }
    }

    return color;
}
#endif